I have a few students who are disturbed about Temple sacrifices (animals,
not grain). One claims it was to give expression to primitive practices
that we picked up in Egypt (G-d getting it out of our system, so-to-speak).
He gives evidence regarding the Golden Calf-- how quick the Jewish people
were to build an animal idol. He also makes a point (which I see as valid)
that if we were to have sacrifices today to atone for our mistakes, we
would show up, give our animal, and it would mean nothing more than
dropping a few coins in a box. If everyone was doing it, it would become
routine.

Others are overwhelmed and turned-off by the blood and gore of it all.